Ok, I have Windows XP (I guess the newer version...idk my dad owns the computer, I'm only 13...LOL) and whenever I START it up, after it says "Welcome", a window pops up that says that Windows hasn't been activated yet, and to click "yes" to activate it. So I click yes, and it shows the desktop but WITHOUT the icons and/or toolbar. and then another window pops up saying that Windows has already been activated, and to click "ok" to exit. So I click ok, and it takes me to the log in screen. I click on the user, and the same THING happens over and over and over again....so yah, idk what to do...  thats SOUNDS pretty wierd. :-? is your copy of windows genuine?(as in NOT pirated) linkinparkluvr224......  
Is this a new computer ?
If it's not a new machine , is this something that has just started ?

dl65    
If that is a real Windows installation AND that CD has not been used to install on another computer CALL Microsoft at the number provided.

If the above is not true you need to get your own copy of Windows for that computer.